The present invention relates generally to leaf springs and, more particularly, to an insert adapted to be disposed between leaf springs to reduce noise.
In a conventional manner, leaf springs are used at each side of a vehicle to provide the suspension mechanism between the frame of the vehicle and the axle. Leaf springs are used in many applications, and more prominently in pickup trucks and other large trucks. The general configuration of a leaf spring includes an upper leaf spring pivotally fixed at one end to the frame and the other end connected via a shackle to the frame of the vehicle. An axle is mounted at an intermediate point along the length of the spring. The arrangement results in a leaf spring having a generally elliptic contour. Usually, a plurality of leaf springs are mounted in decreasing length under the upper spring. The vertical displacement of an axle allows a leaf spring to flex according to factors such as spring thickness and mounting position. As a vertical force is introduced into the leaf spring configuration, the individual springs are encouraged to slidably engage each other as the elliptical contour flattens out and the displacement force is dampened. The sliding engagement of a first leaf spring and a second leaf spring can result in unpleasant frictional noises.
The frictional noise associated with a leaf spring configuration have been addressed by providing a plastic insert having a disk portion and a stem portion. The stem portion is inserted through an aperture in a first leaf spring and the disk portion is aligned for slidable engagement with an opposing, second leaf spring. This approach reduces frictional noise but also presents drawbacks. Often the paint and sediment associated with the coating on a leaf spring becomes trapped between the insert and the spring resulting in added frictional noise. Further, existing inserts do not engage the leaf spring to which they are mounted as positively as possible.
Thus, it is desirable to provide a textured surface on the face of the plastic insert to facilitate removal of the paint and sediments to prevent the formation of high spots on the spring. It is also desirable to provide an increased retention force from the stem onto the inner wall forming an aperture of the leaf spring.
It is an object of the present invention to provide an insert adapted to be disposed between an upper and lower leaf spring that is capable of decreasing the frictional noise created from conventional leaf spring configurations.
It is another object of the present invention to provide an insert having a body including an aperture, a stem having a plurality of fingers including a plurality of radially extending ribs, and a pin adapted to be inserted through a central bore formed from the fingers and causing the side portions to expand in outward directions.
It is a further object of the present invention to provide an insert having a body with a face including a plurality of protruding members which slidably engage the lower surface of an adjacent leaf spring.
It is yet another object of the present invention to provide an insert with a body and a stem having an inwardly extending ridge portion that cooperates to secure an outwardly extending ridge portion on the pin.
It is yet another object of the present invention to provide a pin having a first end and a second end. The first end has an outer diameter that increases when traversing the pin from the first end toward the second end.
It is yet another object of the present invention to provide a one-piece molded component having a body including a stem with a pin interconnected thereto.
It is yet another object of the present invention is to provide a leaf spring insert which is simple in structure, inexpensive to manufacture, and durable in use.
The present invention is directed to an apparatus for reducing frictional noise between leaf springs. The apparatus includes a body having an aperture and a stem having a central bore defined by a plurality of fingers. The plurality of fingers has first and second ends, where the first ends of the plurality of fingers are coupled to a surface of the body around the perimeter of the aperture and projecting away from the surface body. A plurality of retainers are formed on an outer surface of at least one of the plurality of fingers. An insert portion is inserted through the central bore of the stem, thereby expanding the fingers in outward directions.
This invention is also directed to a leaf spring assembly including a first leaf spring and a second leaf spring having an aperture. An insert is disposed between the first and second leaf springs. The insert includes a body portion and a stem portion. The stem portion has a plurality of fingers adapted to be inserted through the aperture of the second leaf spring. A pin is adapted inserted through a central bore formed by the plurality of fingers, thereby displacing said first and second fingers outwardly to engage said aperture.
This invention is also directed to a method of reducing frictional noise associated with a first leaf spring and an adjacent second leaf spring. The method includes the step of molding a one piece component including a base, a stem portion having a central bore, and a pin interconnected to the stem portion. The method also includes the steps of inserting the stem portion through an aperture in a first leaf spring and removing the pin from the stem portion and displacing the pin into the central bore.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood however that the detailed description and specific examples, while indicating preferred embodiments of the invention, are intended for purposes of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.